The Port Bougainville Trail is a loop you can hike or bike to explore the frontcountry of this 2,500-acre preserve. About half of it is easy, while the rest is rugged and tricky to follow in spots.
It provides overlooks into the quarries dug in the middle of the tropical forest, and rugged coral rock to wander over into tidal flats.
On our attempt to do the loop, the tidal flats and quarry were too innudated to ride across. Be mindful of tide charts and water levels in Key Largo.
The fact that there is a “Half Loop” option lets you still explore a minimum of a 1.2 mile loop even when conditions don’t work for the full loop.
Resources for exploring the area
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Location: Key Largo
Length: 2.4 mile loop
Trailhead: 25.1761, -80.3695
Address: CR 905 & MM 106, Key Largo
Fees: $2.50 per person at honor box. Includes per-person Monroe County surcharge
Restroom: Composting toilet
Land Manager: Florida State Parks
Open 8 AM until sunset daily. Leashed pets and bicycles welcome.
Stay on the pathways! Avoid biking down narrow side trails and do not bushwhack.
There are poisonwood and machineel trees throughout the hammock, both of which can cause severe reactions for anyone allergic to poison ivy.
We were advised by an FWC officer not to do this hike during the summer months due to the ferocity of the biting insect population.
As this is a botanical state park, no mosquito control spraying is done here, unlike throughout most of the Florida Keys.
Driving north on US 1 from John Pennekamp Coral Reef State Park, keep right at the fork for SR 905 (to Card Sound Rd). The trailhead parking area is on the right after 0.5 mile, in front of a large archway.
Park next to the archway and follow the pavement into the woods, stopping at the iron ranger to pay your state park entrance fee.
If you’re wondering about the strange look of this entrance, welcome to the Port Bougainvillea that never was, a 1980s condo development that collapsed.
Fortunately, it failed just in time for the state to swoop in and save this incredible botanical wonder before much bulldozing started.
The trail curves past a composting privy, and reaches a major intersection in the pavement, with an island of planted trees and a picnic shelter in the middle.
It’s here you see the first Port Bougainville Trail sign. Turn right.
Pay attention to the plant identifications and notice the differences between the trees, although they seem to blend together on both sides of the old road.
Not far off into the woods in this section are the grand champion roughleaf velvetseed and boxleaf stopper, at 17 feet and 19 feet, respectively.
Of the all of the grand champion trees in the hammock, few of them reach 30 feet tall—the 34-foot blolly being a notable exception.
As you pass a bench to the start of a stone wall on the left, watch for a break in the wall at a quarter mile.
That’s the Nature Trail, which meanders off into the hammock and is not open to bicycles. Pass that by and stay on the paved path.
As open sky appears ahead, the pavement ends. Continue along a rough limestone path through a disturbed piece of tropical hammock. Arrows mark the route.
The forest closes in again, providing dappled shade, and you can see one of the quarries through the trees to the left.
At a junction with a “Half Loop” sign, continue straight ahead, following the “Full Loop” sign.
A side trail to the left soon after led to a view of the quarry where a ramp once crossed to the opposite side but was now under water.
Past this stop, the trail leads out of the tropical forest onto a rocky berm on the edge of a coastal prairie.
Making a sharp left at a T with an “Area Closed” sign to the right, the trail started to parallel a mangrove swamp.
Although the coral rock kept the trail mostly out of the water, salt water lapped up to its edges and created puddles.
Eventually the trail plunged into the salt water at a mile. We walked along it a little trying to figure out where it went next.
As we were riding our bikes, we chose to turn around rather than try to make our way through an unknown amount of squishy salt flats.
Returning to the “Half Loop” sign at 1.2 miles, we made a right and followed the trail through a tunnel of tropical forest to the other side of the quarries.
At the T intersection with the west side of the loop, make a right.
It’s here we lost the trail again. We think that’s because a “Service Vehicles Only” sign was blocking the route shown on our map.
We turned right at that sign and the path clearly led us into an open area adjoining the quarry viewpoint from the other side.
Searching around this area, we could not find a continuation of the loop through it, just tall grass and trees hemming in social trails.
Turning around, we continued south along the west side of the loop, passing the Half Loop crossover.
The trail adjoined another large quarry, this one with a panorama from its shoreline.
Enjoy the views from the edge, but be aware of the poisonwood trees with their black oozy blotches and avoid brushing against them.
Continuing along, the trail is in the tropical hammock and broadens to the width of a road.
You can hear cars along Card Sound Road, which isn’t all that far from the trail. The trail curves left, and quickly brings you to the picnic table and butterfly garden.
Turn right to exit out to the parking lot to complete the trail. Our route, not being able to complete the loop, took 3 miles.
As long as you can traverse the trail (our missing link shown in blue) across the coastal prairie, the outer loop is 2.4 miles.
Learn more about Dagny Johnson Key Largo Hammock Botanical State Park
A botanical treasure rescued from developers, Dagny Johnson Key Largo Hammock Botanical State Park has the highest concentration of National Champion trees in the United States
See our photos of Key Largo Hammock
More worth exploring while you’re in this area.
Protecting more than 6,700 acres of Key Largo to provide prime habitat for the endangered American crocodile, Crocodile Lake NWR has a small visitor complex where you can learn about species conservation at the refuge.
If you’ve ever wondered where Key limes came from, take a walk on the 0.5-mile Grove Trail at John Pennekamp Coral Reef State Park to see of one of the historic groves of Key Largo.
Tunneling into the deep shade of the Key Largo Hammock, a tropical forest that once covered most of the uplands of this island, the Wild Tamarind Trail provides you a close-up look at the trees and shrubs that make up this not-so-common forest.